The SFPD crime lab has been hit with another scandal as authorities confirm that "irregularities" may affect numerous hundreds of cases relying on DNA evidence.

On Friday, the SFPD announced that a lab technician and her supervisor were put on leave while they investigated violations of testing standards. The allegations apparently stem from a trial from last year where child molestation suspect Marco Hernandez was found guilty. In a letter written by Bicka Barlow, a DNA expert who advises the public defender's office, the evidence from the lab was submitted as "definitive" when it was actually incomplete. Allegedly, the technician filled in gaps in the DNA profile.

"I allege that serious misconduct, which substantially affects the integrity of forensic results, has occurred," she wrote to chief Greg Suhr in a letter obtained by the Chronicle dated March 6. Barlow has filed her complaint with not only the SFPD, but also the FBI and the national crime lab accrediting agency.

"This raises a big red flag, and the prosecutor's office should be paying attention to this. They should not just accept this kind of evidence without more scrutiny," she adds.

According to the letter, the lab generated two incomplete DNA samples in 2013 that pointed to numerous suspects, including Hernandrez, but testified that they had definitively matched Hernandez. He confessed to "some elements of the crime" and was found guilty at trial.

The incomplete results were also submitted to a state database, which is in violation of the state's rules.

In response to the allegations Chief Suhr has put both the lab personnel on leave while the matter was being investigated. Suhr says the supervisor failed to catch the misconduct and intervene. The department is analyzing how many cases may have been affected, and Suhr said "it is in the hundreds."

District Attorney George Gascón ordered the investigation and said, "I want the public to know I take this very seriously—we are going to get to the bottom of this, because this is completely unacceptable."

Gascón is no stranger to police lab scandals, having been the chief of police who ordered the shutdown of the lab five years ago after employee Deborah Madden admitted she stole cocaine that was submitted as evidence.

The new revelations come at a bad time for the SFPD, as they are expected to terminate several cops for sending racist text messages.